1. Field of the Invention
The present invention is directed to a hydrogen fueling station, and, more particularly, to a control system for use in a fuel processor.
2. Description of the Related Art
There are numerous uses for pure hydrogen or hydrogen-enriched gas streams. For instance, fuel cells—a promising alternative energy source—typically employ hydrogen as a fuel for generating power. Many industrial processes also employ hydrogen or hydrogen-enriched gas streams in a variety of fields for the manufacture and production of a wide assortment of end products. However, pure hydrogen is not available as a natural resource in a form that can be readily exploited. As a counter-example, natural gas, a hydrocarbon-based fuel, is frequently found in large subterranean deposits that can be easily accessed and transported once tapped. Nature does not provide such deposits of hydrogen.
One way to overcome this difficulty is the use of “fuel processors” or “reformers” to convert hydrocarbon-based fuels to a hydrogen rich gas stream which can be used as a feed for fuel cells. Hydrocarbon-based fuels, such as natural gas, liquid petroleum gas (“LPG”), gasoline, and diesel, require conversion for use as fuel for most fuel cells. Current art uses multi-step processes combining an initial conversion process with several clean-up processes. The initial process is most often steam reforming (“SR”), autothermal reforming (“ATR”), catalytic partial oxidation (“CPOX”), or non-catalytic partial oxidation (“POX”). The clean-up processes are usually comprised of a combination of desulfurization, high temperature water-gas shift, low temperature water-gas shift, selective CO oxidation, or selective CO methanation. Alternative processes include hydrogen selective membrane reactors and filters.
However, safety issues can arise. Consider a hydrogen fueling station for refueling fuel cell powered vehicles that employs a fuel processor. Fuel processing involves pressures and temperatures that, if not controlled properly, could damage the equipment or create harmful conditions for the operators. Moreover, depending on the nature of the fuel processor, both the reactants reformed and the hydrogen produced can require careful control and handling. The hydrogen produced by a fuel processor is also typically stored under pressure until it can be dispensed, which also needs appropriate controls. Thus, new and better control strategies are desirable.